2023-06-27 13:37:00
Last fall, many newborns and toddlers had to be hospitalized with pneumonia. The culprit was RSV: the virus is everywhere and infects most of us more than once in a lifetime. But it can only be dangerous for the little ones. It is possible that their mothers will soon be able to get vaccinated during pregnancy and thus immunize their newborns.
The history of vaccines against RSV begins with a shock: In the 1960s, doctors vaccinated a group of small children with a form of the virus weakened by formalin. At first it looks good, the preparation is well tolerated. But a few months later, 80 percent of those who have been vaccinated have to go to the hospital. Two of the children die.
What happened then?
Open box Close box
After the vaccination attempt, the children, like almost all their peers, were infected with RSV. But not only did the vaccination not protect them, they also made them susceptible to severe courses, as vaccine researcher Jason McLellan from the University of Texas at Austin explains. We now know that the immune system of the vaccinated children was overstimulated and therefore triggered strong inflammatory reactions.
These events had implications for the continued search for RSV vaccines. Almost all clinicians and doctors kept their hands off it – but not basic researcher Jason McLellan. In order to build good vaccines, you have to know exactly what a virus protein looks like, which the vaccine should match, he emphasizes.
Meticulously designed vaccine
Structural biologist McLellan sounds like someone who enjoys playing with Lego, finding his Lego bricks in biology, viruses, antibodies and vaccines. In 2008, he took on the RS virus rather by accident. He looks at the virus structure in great detail and discovers something crucial.
“The RS virus has spikes on the surface, similar to the corona virus,” explains McLellan. The crux of the matter: RSV’s spines change shape as the virus infects body cells. And a vaccine is only effective if it targets the first, unmodified form. Using all sorts of biochemical tricks, McLellan then manages to design just such a vaccine candidate.
Vaccine approved in US and EU
The first RSV vaccines from the pharmaceutical companies GlaxoSmithKline and Pfizer were finally approved in the USA a few months ago, in spring 2023. The EU has so far approved that of GlaxoSmithKline, in Switzerland the company’s application is being examined.
The immunity of the expectant mother is transferred to the newborn.
However, the vaccines have so far only been approved for adults everywhere. Although RSV is also a common cause of pneumonia in older people, the actual target group for a vaccine is young children. So far, however, neither of the two vaccines has been tested on them – not least out of caution after the experiences in the 1960s.
Vaccinate pregnant women and thus immunize fetuses
Pfizer is now trying to get approval for its vaccine to immunize pregnant women in the third trimester. “The immunity transfers to the newborn and protects it in the first six months of life, the period in which RSV is most likely to lead to hospital admission,” says basic researcher McLellan.
The fact that the vaccination could at best lead to a little more premature births is causing discussions. The data on this is still being evaluated. Here, too, one proceeds cautiously after the experiences of the past decades.
But one thing is clear: an effective RSV vaccine is within reach.
1687880560
#Stubborn #cold #virus #hope #vaccination #virus #News